Project Type

Description

Barrier Island Restoration

Barrier island restoration projects involve deposition of dredged material to increase island height and width, and may include placement of engineered structures which protect the island from erosive forces. In many cases, sand-trapping fences are used in conjunction with vegetative plantings to build and stabilize sand dunes on barrier islands.

Dredged Material/ Marsh Creation

Dredged material and marsh creation projects involve the beneficial use of sediment material that is frequently dredged for navigational channel maintenance or for access canals. The material is placed in an open-water area of deteriorated wetland, at a specific elevation, so that desired marsh plants will colonize and grow to form new marsh.

Freshwater Diversion

Freshwater diversions involve diverting the upper portion of a river¹s flow, using siphons or gates, into a deteriorated marsh which will benefit from freshwater input. Nourishment of the marshes with the fine sediment and nutrients suspended in the river water is a secondary benefit of this restoration technique.

Hydrologic Restoration

Hydrologic restoration projects involve changing human-altered drainage patterns back toward natural drainage patterns in an attempt to address problems associated with saltwater intrusion and marsh impoundment. At the large end of the scale, this technique may involve locks or gates on major navigation channels; on a smaller scale, it may involve blocking off dredged canals, repairing breaches of natural boundaries or cutting gaps in banks formed by dredged material placement during canal dredging.

Marsh Management

Marsh management projects were historically used to manage land for waterfowl and furbearers. This wetland restoration technique involves controlling water levels in an enclosed marsh area. A variety of structures can be employed with different capabilities of altering water levels in order to achieve the desired vegetation and wildlife habitat, or to restore severely altered habitat to a more productive state.

Outfall Management

Outfall management projects are used to maximize the benefits of a freshwater diversion project, this technique involves controlling water levels and direction of water flow to increase dispersion and retention time of freshwater, nutrients and sediment in the marsh.

Sediment Diversion

For a sediment diversion, a river levee is cut to allow sediment-laden river water to flow and deposit its sediment into a shallow, open pond, creating new marsh in the form of a crevasse-splay. This technique is an attempt to mimic natural deltaic processes that occurred historically during major flood events.

Sediment and Nutrient Trapping

Sediment and nutrient trapping projects involve structures designed to slow water flow and promote sediment deposition. This restoration technique creates new land and protects nearby marshes. Examples include brush fences, which work best in low-energy environments, and shallow-bay terraces, which involve a network of land ridges formed with dredged material in place of shallow, open water.

Shoreline Protection

Shoreline protection projects involve various techniques designed to decrease shoreline erosion rates. Some techniques, such as rock berms and earthen levees, are applied directly to the eroding shoreline. Other techniques, such as segmented breakwaters and wave-damping fences, are applied in the open water to decrease wave energy before it hits the shoreline and to promote sediment deposition.

Vegetation Planting

Vegetation planting projects are often used in conjunction with shoreline protection, barrier island restoration, marsh creation and sediment and nutrient trapping restoration techniques. This technique involves the use of salt- and flood-tolerant marsh plants, most commonly smooth cordgrass (Spartina alterniflora) in brackish-saline conditions and California bulrush (Scirpus californicus) or giant cutgrass (Zizaniopsis miliacea) in fresh-intermediate conditions. These species will bind sediments together and stabilize the soil with their roots as they become established and colonize a new area.